SYDNEY, AUSTRALIA – Assisted reproductive technologies are associated with cardiovascular remodeling that is present early in fetal life, a study has shown.
The prospective cohort study of 70 fetuses conceived using assisted reproductive technologies (ART) and 70 fetuses conceived spontaneously found significantly increased aortic mean intima-media thickness in ART fetuses compared with controls (0.55 vs. 0.46 mm, P = 0.016).
Dr. Fatima Crispi
ART fetuses had dilated atria compared with controls, as measured by the right atrium/heart ratio (1.6% vs. 1.45%, P = 0.011), more globular hearts, thicker myocardial walls (interventricular septum thickness, 2.8 vs. 2.4 mm; P = 0.001), and impaired relaxation (mitral e’, 8 vs. 8.4 cm/s, P = 0.002).
While the results were statistically highly significant, Dr. Fátima Crispi said that clinically these changes did not represent a disease state, but rather a risk factor.
"To have, for example, increased intima-media thickness or a more hypertrophic heart is not a disease, so it doesn’t mean that these children will have symptoms or problems in the short term, but some of the changes that we are reporting are well-known risk factors for later in life," Dr. Crispi said in an interview.
The study also found ART fetuses had significantly decreased tricuspid ring displacement (5.5 vs. 6.5 mm, P less than 0.001), according to a presentation at the International Society of Ultrasound in Obstetrics and Gynecology world congress.
Dr. Crispi said awareness of cardiovascular issues in ART children had come about only relatively recently, with studies suggesting an increased incidence of hypertension and vascular dysfunction. However, she said this was the first study to examine the cardiovascular systems of ART babies in utero.
"Just by our experience in other prenatal conditions that are remodeling [the cardiovascular system], then you could see that the children have hypertension, so we could infer that if these [in vitro fertilization] children had changes in blood pressure, we would be able to see something prenatally," said Dr. Crispi, a fetal medicine specialist at the fetal medicine research center, Hospital Clinic of Barcelona.
"We did echocardiography and we looked at everything that could be measured; we looked at all the function because we really didn’t know what we were going to find."
Researchers conducted fetal echocardiography at 28 weeks’ gestation, including cardiac morphometry and tissue Doppler ultrasound, and the results were adjusted for birth weight and preeclampsia.
The mechanism of the association is unclear; however, Dr. Crispi suggested it was likely to be a combination of maternal risk and the impact of fertility treatments.
"We have these couples who have some infertility problems; usually the mothers are older – although we adjusted by age; they have more medical diseases, and they have most probably more genetic predisposition to have problems," Dr. Crispi said. "Then this couple goes through all this manipulation of the embryo, and then they receive treatment – hormones and things that could also affect the fetus – so we don’t know if it’s one factor or several factors."
While Dr Crispi stressed that the cardiovascular remodeling did not represent cardiovascular disease, she said awareness of the potential increased risk could help with early prevention and risk factor management in later life.
No conflicts of interest were reported.